This invention relates to an optical Connector for an endoscope.
An endoscope system, as disclosed in Japanese Laid-Oppen (Kokai) Patent Application Nos. 47014/81 and 4015/86 and Japanese Patent Publication No. 53525/88, comprises, as main components, an endoscope and a light source device optically connected together.
The endoscope comprises, for example, a manipulation body, a flexible insertion portion extending forwardly from the manipulation body, a rigid portion mounted on the distal end of the insertion portion, and a flexible cable extending laterally from the manipulation body. An optical connector of a cylindrical shape is mounted on the distal end of the cable. The endoscope further comprises a light guide having a bundle of optical fibers. One end face of the light guide serves as a light-emitting surface, and is optically connected to an illumination window provided at the rigid portion of the endoscope. The light guide passes through the insertion portion, the manipulation body and the cable and is fixedly fitted in the cylindrical connector. The other end face of the light guide serves as a light-receiving surface, and is disposed at or near a port or opening of the cylindrical connector provided at the distal end thereof. The fixing of the connector to the light guide is described in detail in the above Japanese Laid-Open Patent Application No. 47014/81.
The light source device comprises a housing, and a light source accommodated within the housing. The light source generates a convergent illumination light, and usually comprises a lamp and a concave mirror.
The connector is inserted into the housing of the light source device, and in this inserted condition, the distal end of the connector is disposed in opposed relation to the light source. The illumination light from the light source is incident upon the light receiving surface of the light guide, and passes through the light guide, and this illumination light further goes out of the light-emitting surface of the light guide and passes through the illumination window into a body cavity.
In order to observe the body cavity over a wide range, it is desired that the outgoing illumination light be emitted at a wide angle from the illumination window of the endoscope.
To achieve this, the following procedures have conventionally been employed.
First, the light source has been designed for the above purpose. More specifically, the light source as disclosed in the above Japanese Laid-Open Patent Application No. 47014/81 includes a convex lens in addition to the lamp and the concave mirror, so that the angle of convergence of the illumination light generated from the light source is widened or increased, thereby widening the angle of the illumination light incident on the light receiving surface of the light guide. The angle of the outgoing illumination light from the light-emitting surface of the light guide is equal to the angle of the illumination light incident on the light-receiving surface of the light guide. Therefore, by widening the angle of the incident light, the angle of the outgoing light can be widened as described above. However, this arrangement has a disadvantage that the light source device becomes bulky or large-sized.
Secondly, as disclosed in Japanese Laid-Open Patent Application No. 130134/81, a concave lens is disposed between the illumination window and the light-emitting surface of the light guide, thereby further widening the angle of the outgoing illumination light from the light-emitting surface of the light guide. However, this results in a problem that the rigid portion connected to the distal end of the insertion portion becomes complicated and bulky in construction.